PROCEEDINGS of the HUMAN FACTORS AND ERGONOMICS SOCIETY 39th ANNUAL MEETING-1995 989 AUDIBILITY PROBLEMS WITH FIRE ALARMS IN APARTMENT BUILDINGS

A previous study of apartment building evacuation drills showed that as many as 25 % of the occupants mentioned not hearing the fire alarm from inside their apartments. A new experiment was developed to observe evacuation drills and to measure the sound level of the fire alarms in three high-rise apartment buildings. These buildings, built during the 198O's, met the local building regulations regarding the provision of fire alarms at the time of construction. Each building contained approximately 200 apart-ments, with 1 to 4 persons per apartment. For each building, the printed fire safety procedures stated that all occupants should leave the building or move to an area of refuge, upon hearing the building fire alarm. During each evacuation drill, video cameras, were located in corridors and staircases, to record the movement time and behaviour of occupants. Using a digital audio tape recorder, precise sound samples of the fire alarm and background noise were taken from different locations in the buildings. Analyses of the alarm sound spectrum and levels were performed. Results confirm the subjective assessment of occupants who mentioned not hearing the fire alarm in specific locations of the building. It was also found that, in some other areas, the alarm was overpowering. The impact of alarm audibility on fire safety is discussed